1. Field of the Invention
The present invention relates generally to clamp assemblies for connecting one member to a support member. In a particularly preferred aspect, the invention relates to an ultra high strength clamp assembly to attach a pipe or line, such as an umbilical line, to another pipe. In a specific embodiment, the invention is particularly adapted for use as a subsea clamp assembly to attach an umbilical line to a choke or kill line of a subsea riser. In the specific embodiment the invention is particularly adapted for use as a variable height stand-off assembly to attach an umbilical line to a choke or kill line in a marine riser assembly.
2. Background of the Invention
The need often arises for a clamp assembly to attach a cable, hose or pipe to a support member or pipe. The situation often occurs where an umbilical line is required to be secured to a support member or pipe at a certain distance away from the support member, for example, to accommodate insulation, floatation and mechanical barriers.
In the offshore drilling and production industry, it is frequently necessary to run umbilical lines hundreds and even thousands of feet below the support vessel or drilling or production platform down to the sea floor and beyond. Typically, the umbilical lines, which may include electric, MUX (fiber optics), and hydraulics, are required to be attached to a support member, such as a choke or kill line, or mud line on a subsea riser system. Due to the high cost of working in such environments, it is critical that the clamp assembly be reliable and dependable to firmly secure the clamped members to prevent costly consequences, such as loss of signal in a fiber optic cable due to slack in an umbilical line which can create a sharp radius in the line preventing signal transmission. Various types of clamp assemblies and stand-off assemblies have been used in these situations. The prior art clamp assemblies and stand-off assemblies have been very costly and time consuming to make, use and install, and many do not clamp the umbilical lines with enough force.
In my earlier patent application, Ser. No. 09/523,765, a clamp assembly was proposed which overcomes many of the above noted deficiencies. This invention makes improvements to the design shown in my earlier application to provide even greater reliability and ease of use in the field.
The invention provides an improvement to the clamp assembly shown in my earlier copending application. This clamp assembly comprises an upper clamp half, a lower clamp half, a hinge pin connecting the halves, and a fastener latching the halves. The upper clamp half has a downwardly facing parting line face. The lower clamp half has an upwardly facing parting line face and is positioned in a face to face relationship with the upper clamp half so that the parting line faces are side by side. The hinge pin pivotally connects the clamp halves along a hinge edge. A fastener connects the clamp halves along a latch edge. The clamp halves, when positioned the clamp closed position, define at least one passage therethrough for clamping a cylindrical object, wherein the passage has a longitudinal axis. The improved fastener mechanism comprises providing an upper flange element which protrudes from the latch edge of the upper clamp half in a direction, when in the clamp closed position, generally laterally from the longitudinal axis of the passage, and a lower flange element protruding from the latch edge of the lower clamp half in a direction generally laterally from the longitudinal axis of the passage. The lower flange element is in side-by-side relationship with the upper flange element when the clamp assembly is in the closed position, and further defines a passage for receipt of a carrier pin. A carrier pin is rotatably positioned in the carrier pin passage. The carrier pin has a longitudinal axis and defines a transverse borehole for receipt of a locking bolt. A locking bolt having a shaft end is positioned in the transverse borehole and extends radially from the carrier pin. The locking bolt has a head end which is spaced apart from the carrier pin. The upper flange element and the lower flange element define a pair of aligned slots when the clamp assembly is in the closed position to permit the locking bolt to be pivotally moved from a disengaged position wherein the head of the locking bolt laterally displaced from the lower flange element to a lockable position wherein the shaft of the locking bolt is positioned in the aligned slots. The head of the locking bolt is sized to contact the upper flange element when the locking bolt is in the lockable position so that threading the locking bolt toward the carrier pin urges the upper flange element toward the lower flange element to lock the clamp assembly in the closed position.
The invention provides a locking mechanism which has greater reliability than the earlier embodiment and has no loose parts.